1. Field of the Invention
This invention relates to a method and apparatus for curing of articles, and more particularly, this invention relates to a method and apparatus for contacting wet resin-coated articles with a curing agent in a curing chamber for curing of the resin coating.
2. Description of the Prior Art
Resin-coated articles, such as panels, can be cured by passing the wet resin-coated articles through various heat treatment stages. Alternatively, radiation or electron beam and ultraviolet ray systems have been proposed. When heat treatment is employed, the materials or substrates which react to heat will be affected, while in the case of the radiation type of curing, the curing is restricted to the specific area of the path of the beam employed. Such systems, in general, are not desirable since they present considerable safety hazards which need to be avoided by expensive safety precautions and these add to the considerable inherent costs of such known systems.
It is also known, as disclosed, for example, in U.S. Pat. No. 3,411,940, Lopez et al, issued Nov. 19, 1968, to use a tertiary amine in a particular solution as curing agent or catalyst. Curing agents, such as tertiary amines, are very effective, usually providing for curing when in the vapor phase in a few seconds of exposure to the item that is to be cured. However, the handling of these vaporous curing agents presents considerable problems since the vapor is highly toxic and use of these vapors must be strictly confined to curing.
In U.S. Pat. No. 3,931,684, Turnbull et al, issued Jan. 13, 1976, there is disclosed an apparatus for curing of articles by means of a tertiary amine curing agent. In accordance with the proposal by Turnbull et al, a curing chamber is provided, which chamber comprises entry and exit ports which are guarded by air curtain means to prevent escape of the toxic gases from the chamber. The air curtain means are connected by communication means, and a controlled heated moist vapor is supplied to the air curtains to substantially reduce or prevent the escape of the volatile gases from within the curing chamber.
The proposal of the Turnbull et al patent has met commercial acceptance, and thus is satisfactory for the containment of the volatile, toxic gases used in such curing operations. However, there is still a need to provide a curing method and apparatus which will yield an improvement in the performance of such curing systems while, concomitantly, being less costly and which at least equal, or exceed, the effectiveness of safety provisions of the prior art systems.